One way of fastening thermoplastic parts together is by the technique of vibration welding. That is, two thermoplastic parts which are to be fastened together are placed into contact and then rapidly vibrated so as to melt their points of contact due to the heat generated by the friction caused by the vibration. Upon solidification, the two parts are welded together. In essence, the two plastic parts are held together tightly and one is rapidly moved back and forth relative to the other to produce friction generated heat.
The technique of vibration welding is useful in producing large numbers of welded together parts at relatively low cost. For this purpose, various types of equipment have been developed in the past. However, because the technique involves applying a relatively rapid vibration, prior equipment has been heavy, large, and expensive. Particularly, the motors used for vibration purposes have been expensive and limited in frequency of vibration. Another disadvantage of previously available equipment has been the necessity for bulky and expensive supporting means to hold the vibrating portions of the apparatus.
Thus, the invention herein relates to a vibration apparatus for rapidly vibrating thermoplastic parts for welding purposes, which apparatus is considerably simpler in construction, less bulky, and less expensive than prior available equipment and which will produce a rapid, low amplitude vibration. The equipment herein has as one objective the performance of the entire operation of vibration for suitable heating, stopping of the vibration and holding of the parts until the weld freeze occurs, in a very rapid time interval, as for example, from considerably less than one second up to several seconds.